1. Field of Invention
The present invention relates to electric drive systems. In particular, the invention relates to an electric drive system having a power conversion circuit coupled to a remote permanent magnet synchronous machine (PMSM) via a high voltage interface cable.
2. Background Art
Electric machines, such as an electric or a hybrid electric vehicle, may employ electrical energy for propulsion via an electric drive system. An electric drive system can encompass a number of components, typically including at least a power circuit such as a power electronics converter (PEC), and a motor. In this arrangement, the power circuit can controllably transfer power from the power source to the motor to drive a load. In the past, the power conversion circuit or the PEC was typically integrated with and packaged with the motor. However, PEC and motor integration is associated with several disadvantages, including higher costs, a more limited selection of suppliers, and reduced PEC reliability.
Separation of the PEC from the motor allows for greater design flexibility and reduced costs. However, if the high voltage inteerface cable that connects a PEC with a remote PMSM becomes disconnected during vehicle operation or during maintenance procedures, it is critical that the high voltage energy within the PEC be discharged. Otherwise, the electronic drive system may continue to generate a high voltage current on the exposed portion, posing a hazard to persons that may come in contact with, or be proximate to the exposed portion. Attempts to address the hazards imposed by a disconnected cable include cable connector designs that decrease the likelihood that the cable will become disconnected. However, such designs have been quite costly and have not been shown to be fail-proof.